/*
 * Copyright 2002-2015 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.test.context;

import org.springframework.context.ApplicationContext;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.lang.Nullable;
import org.springframework.test.annotation.DirtiesContext.HierarchyMode;

/**
 * A {@code CacheAwareContextLoaderDelegate} is responsible for {@linkplain
 * #loadContext loading} and {@linkplain #closeContext closing} application
 * contexts, interacting transparently with a
 * {@link org.springframework.test.context.cache.ContextCache ContextCache}
 * behind the scenes.
 *
 * <p>Note: {@code CacheAwareContextLoaderDelegate} does not extend the
 * {@link ContextLoader} or {@link SmartContextLoader} interface.
 *
 * @author Sam Brannen
 * @since 3.2.2
 */
public interface CacheAwareContextLoaderDelegate {

    /**
     * Load the {@linkplain ApplicationContext application context} for the supplied
     * {@link MergedContextConfiguration} by delegating to the {@link ContextLoader}
     * configured in the given {@code MergedContextConfiguration}.
     * <p>If the context is present in the {@code ContextCache} it will simply
     * be returned; otherwise, it will be loaded, stored in the cache, and returned.
     * <p>The cache statistics should be logged by invoking
     * {@link org.springframework.test.context.cache.ContextCache#logStatistics()}.
     *
     * @param mergedContextConfiguration the merged context configuration to use
     *                                   to load the application context; never {@code null}
     * @return the application context
     * @throws IllegalStateException if an error occurs while retrieving or loading
     *                               the application context
     */
    ApplicationContext loadContext(MergedContextConfiguration mergedContextConfiguration);

    /**
     * Remove the {@linkplain ApplicationContext application context} for the
     * supplied {@link MergedContextConfiguration} from the {@code ContextCache}
     * and {@linkplain ConfigurableApplicationContext#close() close} it if it is
     * an instance of {@link ConfigurableApplicationContext}.
     * <p>The semantics of the supplied {@code HierarchyMode} must be honored when
     * removing the context from the cache. See the Javadoc for {@link HierarchyMode}
     * for details.
     * <p>Generally speaking, this method should only be called if the state of
     * a singleton bean has been changed (potentially affecting future interaction
     * with the context) or if the context needs to be prematurely removed from
     * the cache.
     *
     * @param mergedContextConfiguration the merged context configuration for the
     *                                   application context to close; never {@code null}
     * @param hierarchyMode              the hierarchy mode; may be {@code null} if the context
     *                                   is not part of a hierarchy
     * @since 4.1
     */
    void closeContext(MergedContextConfiguration mergedContextConfiguration, @Nullable HierarchyMode hierarchyMode);

}
